This invention is directed specifically to the production of tantalum and columbium powders. These powders have the characteristic of producing very high capacitive charge anodes for the manufacture of electrolytic capacitors. Production of these powders is conducted in a liquid phase with a selected combination of various means of control in order to produce specifically desired particle sizes at a high yield and high rate of production. In a preferred aspect, the invention provided the means of control for the reaction, EQU K.sub.2 TaF.sub.7 +5Na.fwdarw.Ta+2KF+5NaF
in order to obtain various desired metal powder particle sizes. The means of control for particle size are primarily the sodium metal addition rate, the heat extraction rate from the exothermic reaction by means of forced cooling, and the addition of diluent salts to serve as an internal heat sink in the bath to enhance sodium metal addition rates.
For convenience of description, the invention is disclosed herein primarily as it relates to the reduction of potassium fluotantalate double salt (K.sub.2 TaF.sub.7) by metallic sodium in accordance with the above equation.